1. Field of the Invention
The present invention relates to an evaporated fuel treating apparatus.
2. Description of Related Art
An evaporated fuel treating apparatus (hereinafter also referred to as a canister) which temporarily adsorbs fuel components in evaporated fuel has been used to prevent evaporated fuel from an automobile fuel tank or the like from being emitted into the atmosphere.
In recent years, canisters have been expected to reduce a dissipated amount of evaporated fuel into the atmosphere. As a canister which reduces a dissipated amount of evaporated fuel into the atmosphere, there is known a canister 101 disclosed in JPA-2001-323845 as shown in FIG. 10. The canister 101 includes a case 105 having a tank port 102, a purge port 103, and an atmospheric port 104. In the case 105, a main adsorption chamber 106, a second adsorption chamber 107, and a third adsorption chamber 108 are formed in order from the tank port 102 side. Activated carbon is provided in the main adsorption chamber 106, second adsorption chamber 107, and third adsorption chamber 108. A plate member 109 having a restriction portion for restricting diffusion of evaporated fuel is provided between the second adsorption chamber 107 and the third adsorption chamber 108.
The canister 101 has the plate member 109 having the restriction portion provided between the second adsorption chamber 107 and the third adsorption chamber 108 to thereby restrict diffusion of evaporated fuel from the second adsorption chamber 107 into the third adsorption chamber 108. This restricts escape of evaporated fuel components to the outside through the atmospheric port 104.
Although the plate member 109 in the conventional canister 101 has the restriction portion, a space formed by the plate member 109 provided between the second adsorption chamber 107 and the third adsorption chamber 108 has no adsorption capability and is less effective in delaying diffusion of evaporated fuel components from the second adsorption chamber 107 into the third adsorption chamber 108. It is thus desirable to reduce evaporated fuel components escaping to the outside through the atmospheric port 104 by delaying diffusion of evaporated fuel components into the third adsorption chamber 108 much longer and reducing evaporated fuel components left in the third adsorption chamber 108.